Au (Alemannic German: Ou) is a town in the Bregenz Forest in Vorarlberg (Austria).

It consists of several districts: Am Stein, Argenau, Argenstein, Argenzipfel, Jaghausen, Kreuzgasse, Lebernau, Lugen, Lisse, Rehmen, Schrecken, and Wieden.

The first known inhabitants of the Au region were the Alemanni, primarily from the Vorarlberg Rhine Valley or the Bregenz area.

The land comprising the modern municipality was originally owned by King Rudolf of Habsburg, who later ceded it to the Counts of Bregenz-Montfort.

During this period, the name ‘Jaghausen in den Owen’ originated, reflecting the counts' construction of a hunting lodge there.

The Thumb and Beer families of master builders, based in Au, developed the Baroque Vorarlberg cathedral style in the 17th century.

[4] Master builders and craftsmen from the Bregenz Forest in particular, but also from other parts of today's Vorarlberg, played a leading role in the 600 churches and monasteries that were built in the Baroque style in the 17th and 18th centuries.

[5] Members of the Guild of Au received 60 percent of the more than 700 major construction contracts awarded to Vorarlbergers.